Optical fibers maintained as one unit of type ribbon cable, usually called fiber ribbon cable, are increasingly used side by side with "classical" discrete optical fibers. Naturally then, in practical use, interconnections must be made between the discrete optical fibers and the fiber parts of the fiber ribbon cable. This can be a complicated process requiring a lot of time and work, in particular comprising a lot of manual work, which of course causes high costs. There is therefore a need for devices which can facilitate the splicing of individual fibers to a fiber ribbon cable. One possibility is to place end portions of the discrete optical fibers in a narrow slot and parallel to each other and then pressing the fiber ends laterally against each other whereby the discrete fibers are positioned in the same way as the individual optical fiber parts in a fiber ribbon cable.